Systems and methods for optimizing timing phase in modem devices
Systems and methods are provided for performing the required phase calculation in a telecommunications system in order to optimize system performance more quickly and with reduced complexity as compared to prior approaches to solving this problem. In accordance with the preferred exemplary embodiment of the present invention, the phase delay of the precursor equalizer (EQ) is calculated off-line and as a result it is not necessary to fill the precursor EQ delay line with the indicated number of symbols as in the previous approach. Additionally, because the precursor EQ is fractionally spaced, both sine and cosine values of the 4kHz tone's initial phase can be achieved simultaneously. As a result, only 36 quick timing sequence (QTS) symbols are needed in order to perform the required estimation.
1. A method of determining a desired timing phase in a communications device comprising the steps of:
adjusting the timing phase δ such that:
α+β+δ=π/2;
where a α Initial phase before decision feedback equalizer;
β=Equalizer phase compensation;
and determining δ=tan −1 ((tan(α)+tan(β))/(tan(α)·tan(β)) adjusting a timing interpolator to sample the equalized signal.